Tìm phân tử:
1) 6x^4-9x^3
2) x^2y^2z+xy^2z^2+x^2yz^2
3) x^4+x^3+x+1
4) x^3-19x
5) x^4+x^2-1
6) 4a^2b^2-(a^2+b^2-c^2)
7) ab.(a-b)+bc.(b-c)+ca.(c-a)
8) (a+b+c)^3-a^3-b^3-c^3
9) (x^2-8)^2+36
10) 81x^4+4
11) (x^2+x+1).(x^2+x+2)-12
12) (x^2+4x+8)^2+3x.(x^2+4x+8)+2x^2
13) (x+1).(x+2).(x+3).(x+4)-24
14) 3x^3-14x^2+4x+3
15) 12x^2+5x-12yz+12y-10xy-3
Đáp án:
1) 6x^4-9x³
=3x³(2x-3)
2) x²y²z+xy²z²+x²yz²
=xyz(xy+yz+xz)
3) x^4+x³+x+1
=x³(x+1)+(x+1)
=(x+1)(x³+1)
4) x³-19x
=x(x²-19)
6) 4a^2b^2-(a^2+b^2-c^2)
sai đầu bài nha bn
7) ab.(a-b)+bc.(b-c)+ca.(c-a)
==a²b−ab²+bc(b−c)+c²a−a²c
=a²(b−c)+bc(b−c)−a(b²−c²)
=a²(b−c)+bc(b−c)−a(b−c)(b+c)
=(b−c)(a²+bc−ab−ac)
=(b−c)[a(a−c)−b(a−c))
=(b−c)(a−c)(a−b)
8) (a+b+c)³-a³-b³-c³
=(a+b)³+3(a+b)c²+3(a+b)²c+c³-a³-b³-c³
=a³+3a²b+3ab²+b³+3(a²+2ab+b²)c+3(a+b)c²+c³-a³-b³-c³
=3a²b+3ab³+3a²c+6abc+3b²c+3c²a+3c²b
=(3c²b+6abc+3a²b)+3a²c+(3ab²+3b²c)+3a²c
=3b(c²+2ac+a²)+3ac²+3b²(a+c)+3a²c
=3b(c+a)²+3ac(a+c)+3b²(a+c)
=(a+c)(b(a+c)+ac(a+c)+b²)
Giải thích các bước giải:
chúc bn hk tốt